The invention relates to a device conveying flat objects edge-on in series at high speed between an entry and an exit of a conveying path with a routing system for diverting some of these flat objects towards another exit between the entry and the exit of the conveying path, this system comprising two mobile flaps kept mutually parallel and arranged between the entry and the exit of the conveying path, and two motorized endless belts moving between these two flaps and between which the flat objects conveyed are gripped, these two flaps being mounted so that they can pivot so as to route the flat objects either towards the exit of the conveying path or towards the other exit.
A device of this kind is more particularly intended for a machine for automatically processing mail in which it is necessary to extract from the main stream of envelopes conveyed between the destacking unit and the sorting unit of the machine, certain envelopes which are to be rejected before they arrive at the sorting unit, without disrupting the main stream. Machines for processing mail have to be designed to be able to take a broad range of postal items. More specifically, they have to be designed to be able to take flat rectangular envelopes, the thickness of which varies between 0.15 and 32 millimeters while the length and width of these envelopes can vary respectively between 14 and 40 centimeters and between 9 and 30 centimeters.
It is customary for the envelopes for rejection to be diverted using a system comprising two mobile parallel flaps around which the two drive belts are looped. In consequence, in this arrangement, the two belts do not accompany the envelopes all the way to the exit of the conveying device which exit is distant from the two flaps. This break in the conveying device leads to variations in the spacing between consecutive envelopes along the conveying path because of the fact that the two belts let go of the envelopes and these variations in spacing complicate the processing operations performed at the exit of the conveying device.
It is also customary for the envelopes for rejection to be diverted, not using a two-flap system, but using a mobile post. This system is not, however, suited to a broad range of postal envelopes with highly varying thicknesses as mentioned hereinabove.
The object of the invention is to provide a device for conveying flat objects of varying thickness edge-on and in series at high speed using a two-flap system, allowing some of these objects to be diverted from their conveying path without disrupting the main stream of flat objects.
To this end, the subject of the invention is a conveying device as defined hereinabove, wherein: a stationary post is located at the point where the flat objects are routed downstream of the mobile flaps between the entry and the exit of the conveying path; the exit of the conveying path is distant from the stationary post; and one of the motorized endless belts extends beyond the stationary post as far as the exit of the conveying path. Using this arrangement, it will be understood that just one of the two motorized endless belts is looped around a flap to allow the flat objects to be routed on both sides of the post. Because the other motorized endless belt extends beyond the post as far as the exit of the conveying path, the continuity of the conveying of the flat objects is maintained beyond the routing point, and this plays a part in maintaining the spacing between consecutive flat objects. When the flaps are oriented to divert a flat object towards the other exit, this belt is deformed by one of the flaps against the stationary post and this means that the diverted flat object is still gripped between the two belts as far as the routing point.
According to one particular embodiment of the device according to the invention, the two motorized endless belts are gripped together by a pair of elastically deformable elastomer wheels with stationary rotation spindles arranged on each side of the two mobile flaps. This arrangement is far simpler than an arrangement with pulleys mounted on pivoting arms returned by springs which press the two belts together between the two flaps. In addition, such wheels are better able to absorb the variations in thickness of the flat objects and are better able to accompany the diversion of the flat objects.
According to another particular feature of the device according to the invention, the elastically deformable elastomer wheels each comprise a hub mounted to rotate on a stationary spindle and an annular tread strip in contact with one belt, the hub and the annular tread strip of each wheel being connected by elastically deformable circular-arc-shaped fins, the two ends of each fin, which are for connection to the hub and to the annular tread strip of the wheel, lying on a radius of the wheel. With an arrangement such as this, each wheel can absorb great variations in thickness of the flat objects without fatigue, returning to its normal position very quickly.